The world of wireless telecommunications is rapidly evolving. The need for a variety of data delivery mechanisms has led to a number of different communication protocols being established. Among the more familiar such communication protocols for wireless applications are amplitude modulation (AM) and frequency modulation (FM), for radio; global system for mobile communications (GSM), general packet radio service (GPRS) and international mobile telecommunications 2000 (IMT-2000 or 3G), for mobile phones; and a number of protocols based on various IEEE standards, such as 802.11 (WiFi), 802.15.1 (Bluetooth), 802.15.3 (ultra wide band), and 802.16 (WiMax). All such communication protocols offer wireless communication services for different and specific purposes. See e.g., Y. W. S. J. S. Lee and C. C. Shen., “A comparative study of wireless protocols: bluetooth, uwb, zigbee, and wi-fi,” in Proceedings of the 33rd Annual Conference of the IEEE Industrial Electronics Society (IECON), volume 46-51, November 2007.
Among the applications for wireless communications protocols, a promising emerging technology is the wireless sensor network (WSN). The goal of such networks is to connect things rather than people. There are several applications for such technology, including a so-called SmartHome, which imagines a home in which virtually every electronic device is part of a wireless network for energy control, central administration and comfort. Other applications for WSNs include precision agriculture, such as irrigation management; urban monitoring; and air pollution monitoring. Practical use of wireless sensor networks have been described e.g., in J. Panchard, “Wireless sensor networks for marginal farming in India.” PhD thesis, Lausanne, 2008; “Wireless distributed sensing system for environmental monitoring,” available at the Sensorscope project web page of the Ecole Polytechnique Federale de Lausanne.
WSNs are appropriate for those areas where many measurements are necessary in both space and time, and areas where one sensor station is inadequate for monitoring owing to the differing environmental factors and nature of the measurements varying even over short distances. The diversity and complexity of microclimatic variables is described e.g., in P. J. M. J. B. L. Hernandes, J. L., “Seasonal differences among microclimatic variables from environments of forest interior, vineyard and standard weather station at jundia, brazil.” publication, Centro Avanado de Pesquisa Tecnolgica do Agronegcio de Frutas, IAC, Caixa Postal 11, 13200-970 Jundia (SP), Brazil. Usually measurements in these areas require full autonomy of a WSN node. Low energy consumption and battery operation is usually also a requirement.
Several solutions to this problem have been proposed. ZigBee (IEEE 802.15.4) is one such solution. However, the ZigBee approach, among others, proposes a new system design, including new software, hardware and communication protocol components. See e.g., H. S, Bhavneet Sidhu and A. Chhabra, “Emerging wireless standards—wifi, zigbee and wimax,” World Academy of Science, Engineering and Technology 25 2007, Such bottom-up design was intended to address WSN requirements tor extreme long battery life, measured in at least months if not in years, are unlike those faced by previous communication protocols and devices. The adoption of a communications protocol, not widely used, and one which requires new software and hardware, would pose a huge cost to manufacturers, owners and users of ubiquitous 802.11-compliant family for products.